Pin contact for printed circuit boards



Nov. 24, 1964 T. L. RUSH 3,158,418

PIN CONTACT FORPRINTED CIRCUIT BOARDS Filed Feb. 2, 1962 i liit i Hi hil. "i I l H l INVENTOR. THOMAS L. RUSH ATTORNEY United States Patent i3,158,418 PIN (IONTACT FOR PRINTED ClRCUlT BOARDS Thomas E... Rush, lilanhattan illeach, Califi, assignor, by mesne assignments, to the UnitedStates oi America as represented by the Secretary of the Navy Filed Feb.2., 1962, Ser. No. 176,847 1 Claim. (Cl. 339-1") The present inventionrelates to contacts for unitary assemblies of the type known in theelectrical art as printed circuits. This term as used herein is intendedto designate any set of planar conductors and/or components which isbonded to, or otherwise supported by, an insulating board or sheet, suchconductors and/ or components being adapted to replace conventional wireconductors, resistors, capacitors, etc. in an electrical circuit. Theseconductors and/or components may be applied to the insulating board, forexample, by spraying, printing, silk screening, photo-etching orelectrode position.

A majority of the printed circuits now in use are of the modular type.Tln's permits the individual subassemblies in a complex electricalnetwork to be readily interchanged when a difierent operating functionis desired, and also renders each unit easily removable in the eventthat replacement or repair becomes necessary. In recognition of thisfact, substantially all printed circuit boards are built around theprinciple of plugability. This usually required that all of theconductors leading to other sub-assemblies of the network in which anyparticular printed circuit board is utilized be arranged to terminatealong one edge of the circuit board. There are then several possibleways by means of which the components of the circuit board in questionmay be electrically integrated into the remainder of the system.

One common procedure is to provide a connector assembly in the form of arectangular plug of insulating material having a plurality of springcontacts formed therein, each such Spring contact being designed forasso ciation with a particular one of the printed circuit boardconductors. When such a plug is utilized, electrical engagement betweenthe spring contacts and the respective planar conductors of the board isfrictional-in nature, and all such contacting engagements areestablished simultaneously when the plug is brought into operatingposition.

However, there are occasions where it is desirable to provide a separateindividual contact for each one of the terminal conductors of theprinted circuit board. In these circumstances, the alignment of suchcontacts and the spacing therebetween is quite critical, since eachcontact includes an outwardly-projecting portion, or prong, which isreceivable in one of the sockets of a connector block. Hence anymisalignment of even a single one of these contacts may preclude aproper insertion of the prongs as a unit into the female portion of theconnector. When individual contacts of the above type are utilized,rather complex apparatus is usually required to properly mount andposition the contacts on the printed circuit board. Since such amanufacturing operation is performed automatically, misalignedassemblies frequently remain undetected until an actual engagement ofthe unit with a socket is attempted.

The present invention is directed to a printed circuit connector in theform of an individual pin contact which may be readily associated withone of the planar conductors of a printed circuit board. The design ofthis 3,1 58,4 l 8 Patented Nov. 24, 1964 pin contact is such as tofacilitate the assembly operation by which the unit is manufactured byalmost completely eliminating any necessity for extensive tooling.Hence, a substantial reduction in the cost of manufacturing theconnector is achieved.

Briefly stated, this result is achieved through the provision of a pincontact designed with a pair of extending portions, one of which isintended to pass through an aperture in the printed circuit board and tobecome aligned with that particular planar conductor which the contactpin in question is intended to electrically engage. The other of theseextending portions is intended to be associated with one of a series ofevenly spaced notches formed along that edge of the printed circuitboard at which the series of planar conductors terminate. Following aninsertion of the pin contact through these cut-out portions of theboard, the contact is displaced laterally (parallel to the boardsurface) so that one portion thereof looks into the notch. This lockingengagement between the pin contact and board defines the position of thecontact with respect to its particular planar conductor. Also, a spatialrelationship is established between adjacent contacts, since theposition of each contact is necessarily dictated by the location of itsparticular notch, and all of the notches have been pro-formed to beequidistant from one another. Following insertion and subsequentmovement of the contact in the manner set forth, further means areprovided for locking each contact in its desired position by means of aninsertable plug which is receivable within the cut-out portion of theprinted circuit board. Insertion of such plug precludes subsequentmovement of the pin contact during use and maintains the alignment ofthe prongs. The assembly operation by which the device of the presentinvention is fabricated can be performed at high speed and with aminimum number of steps. A plug-in unit incorporating contacts of thenature described is especially applicable to modular electricalequipment, and possesses complete interchangeability with respect toother sub-assemblies with which it may be associated.

One object of the present invention, therefore, is to provide animproved form of connector for printed circuits.

Another object of the invention is to provide a connector for printedcircuits in the form of an individual pin contact for each printedconductor, such pin contact being receivable in, and indexed by, a notchformed along one edge of the printed circuit board.

A further object of the invention is to provide an individual pincontact for printed circuits which is inexpensive in cost and readilyadapted to that particular circuit design into which it is to beincorporated.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

FIG. 1 is a plan view of a printed circuit board which has been modifiedin accordance with the principles of the present invention;

FIG. 2 illustrates a preferred form of contact pin designed inaccordance with the present concept, and sets forth the steps by whichsuch contact pin and circuit board are assembled to form a unitarystructure;

HO. 3 IS an enlarged View of a portion of the printed circuit of FIG. 1showing in greater detail the manner in S which the contact pin isassociated therewith; and

FIG. 4 is a plan view of the contact plug of FIGS. 1 thru 3.

Referring now to that embodiment of the present invention illustrated inthe drawings, there is shown in P16. 1 a more or less conventionalprinted circuit board to which has been modified in a manner to bedescribed. The board ill carries thereon a plurality of planarconductors 12 which serve to interconnect various components (not shown)making up a circuit the design and function of which forms no part ofthe present invention. These conductors 12 are disposed in spaced-apartfashion so as to be essentially parallel to one another andperpendicular to that particular edge 14 of board it) at whichelectrical connections are to be made to other portions of the overallsystem or network of which the circuit in question forms a part.

As best shown in the left-hand portion of FIG. 1, each of the conductorsl2 terminates at the periphery of a circular aperture 1-5 which has beentorme i in board adjacent the edge 14. These apertures lie equidistantfrom the edge 14 of the board, and are of a diameter which is preferablysomewhat greater than the width of the planar conductors.

Associated with each aperture 36 is a notch 18 formed in the edge ll lof board lil. Each of the notches lb is so located that one ofconductors 12 would terminate at such notch were it to be continued tothe edge of the board. The width of each notch lb is slightly less thanthat of each planar conductor 12, as will be noted in the drawing.

In FIG. 2 is illustrated a preferred form of contact pin designed inaccordance with the principles of this invention. Such pin is generallyidentified by the reference numeral 29, and is made up of a body portion22 from which extends a cylindrical prong 2d. Extending in a directiongenerally opposite to that of prong 24 is an elongated side member 26,and at a point near the furthest extremity of side member 26, is formedan L-shaped extension 28. As will be seen in FlG. 2(a), the L-shapedextension 28, together with the terminal portion of the side member 26,defines a U-shaped recess fill.

The body portion 2.2 of pin 2% has extending therefrom a projection 32.,which, together with the side member 26, establishes a further U-shapedrecess 34. referring to FIG. 2(a), it will be seen that the two recesses3b and 34 are aligned vertically (in the drawing) and lie essentially onan axis established by the prong It will be noted that this contact pinas shown in the drawing may be integrally formed, as by stamping, or thepin otherwise fabricated from a single piece of electrically-conductivematerial.

In FIG. 2(a) the Contact pin 2% is shown adjacent the printed circuitcard 14 and ready for assembly therewith. FIG. 2(a) also shows thecircular aperture 16 in card it), as well as the notch 18 alignedtherewith. This relationship of the elements as set forth in FIG. 2(a)is accordingly that which exists prior to the operation by means ofwhich these two members are brought together. If now the contact pin 2%is moved in a direction indicated by the arrow, the relationship of FIG.2(1)) is established. As will be noted, the L-shaped extension 28 hasentered the circular aperture 16 in card it), and, in similar fashion,the contact pin projection 32 has passed through the notch 18 andemerged on the opposite side of the circuit board. It will beappreciated that the vertical dimension of the L-shaped contact pinextension 28 is such as to enable it to pass through the circularaperture 16 in the circuit board.

After the elements have assumed their position as shown in FIG. 2(b),the contact pin 2t is again moved in a direction shown by the arrow,which latter movement is transverse to that which first occurred.Expressed differently, this last-mentioned movement is in a vertical(upward) direction as viewed in the drawings. Following this lattermovement, that portion of the printed circuit board it) which isassociated with the terminal portion of conductor 12 enters into theU-shaped recess 36 in pin 29, while that portion of printed circuitboard 1% adjacent the notch 13 enters into the U-shaped recess 34. Theelements now have the relative position shown in FF. 2(0). It will berecognized that the notch 13 indexes, or precisely determines, theposition of the contact pin 24) laterally along the edge 14-, and thecontact pin is prevented from any transverse displacement by its contactwith the sides of this notch into which the body portion 22 of the pinis receivable. It will be further noted that when the pin it) has movedupwardly as shown in FIG. 2(a), the interior surface of the U-snapcdrecess fa l forms a good electrical contact with the outer surface ofthe planar conductor 12 with which the pin 20 is associated. Anyrelative movement between these two memhers is prevented by means whichwill now be described.

Also shown in FIG. 2 is a metallic contact plug, identified by thereference numeral 36. This plug 36 is generally cylindrical in outline,and has a dimension corresponding to that or" the circular aperture 15in the printed circuit board 159. The plug 35 (a face view of which isalso shown in FIG. 2) has formed therein a notch 38 shaped so as to fitover the L-shaped extension 28 of contact pin In other words, contactplug 3 6 is designed to slide into the circular aperture 16 of the boardit? after the 2% has been inserted therein and the ele ments haveassumed their position as shown in FIG. 2(0). Movement of plug 36 is asshown by the arrow in this latter figure. W'hen plug 36 has entered theaperture 16, the extending portion 23 of pin 2 is held in place by thesides of the notch 38 formed in plug 36 to prevent movement of pin 2%)in any direction whatsoever from its assembled position. When theelements are completely brought together, as shown in FIG. 2(d), a smallbead of solder is placed at the point illustrated between the pin andplug to prevent the latter from leaving the aperture 16.

FIG. 3 is an enlarged view of one of the contact pins of FIG. 1, showingthe appearance of the complete assembly following the solderingoperation mentioned in connection with FIG. 2(d). It is of courseunderstood that the prongs 2d of the pins are intended to be receivablein the socket portion of an adaptor (not shown) from which electricalconnections are made to other portions of the overall system.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. it is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

I claim:

The combination with a printed circuit board of the type carryingthereon at least one planar conductor terminating adjacent the peripheryof said board, said board being formed with a circular aperture thereinat the edge of which said conductor terminates, said board also havingalong the periphery thereof a notch aligned with both said conductor andsaid circular aperture, of a contact pin formed of electricallyconductive material and comprising a body portion, a cylindrical prongextending from said body portion, an elongated side member extendingfrom the body portion of said contact pin in a direction generallyopposite to the general direction in which said prong extends, anL-shaped extension formed on said elongated side member near thefurthest extremity thereof, said L-shaped extension, together with theterminal portion of said side member, defining a first U-shaped recess,and a prog'ection extending from the body portion of said contact pin inthe region of the said side member, said projection, together with thatportion of said side member lying in the region thereof, defining asecond U-shaped recess, whereby, when said contact pin is positionedadjacent said board so that the longitudinal axis of said pin as definedby the axis of said cylindrical prong is parallel to the plane of saidboard, a transverse movement of said contact pin will cause the L-shapedextension thereof to enter said circular aperture and the pin projectionto pass through said notch, whereupon a further movement of said pinparallel to the plane of said board Will cause the terminal portion ofsaid planar conductor to enter said first U- shaped recess in said pinto establish electrical engagement therebetween, while at the same timea portion of said circuit board adjacent said notch enters the saidsecond U-shaped recess in said contact pin, and a generally cylindricallocking plug receivable in the circular aperture of said circuit board,said locking plug having a cut-out portion arranged to pass by theL-shaped extension on said contact pin following the relative movementsbetween said pin and said board by means of which said electricalengagement has been established.

References Cited by the Examiner UNITED STATES PATENTS 2,724,811 11/55Poupitch. 2,962,692 11/60 White. 3,027,538 3/62 Deakin.

JOSEPH D. SEERS, Primary Examiner.

ALBERT H. KAMPE, Examiner.

